DSpace Community:http://hdl.handle.net/2440/14759
Mon, 03 Aug 2015 00:28:12 GMT2015-08-03T00:28:12ZForaminifera from the subsurface Miocene of Wreck Island, Queenslandhttp://hdl.handle.net/2440/93202
Title: Foraminifera from the subsurface Miocene of Wreck Island, Queensland
Author: Lloyd, A. R.
Abstract: Foraminiferal faunas from the Miocene limestones, sandstones and siltstones penetrated by HBR No . 1 Bore (530-1795 feet) have been studied; the "smaller" foraminifera in some detail. The sequence is overlain disconformably by Recent-Pleistocene limestones and sandstones (0-530 feet).
The Wreck Island faunas afford an important link between the biostratigraphically significant "larger''and planktonic foraminifera. The occurrence of Lepidocyclina (Nephrolepidina) enables correlation with the “F" Stage of Indonesia and with the New Zealand sequence. Globoquadrina altispira altispira (Cushman and Jarvis) appears immediately above, associated with Orbulina universa d'Orbigny and Globorotalia menardii menardi
(d'Orbigny). This part of the sequence can thus be correlated with the sequences in Trinidad, Venezuela and Victoria. The occurrence of Globigerina mayeri (Cushman and Ellison) and Pulleniatina praeobliguiloculata n.sp . enables part of the sequence above to be correlated with Trinidad, Venezuela, Victoria, Indonesia and Saipan, Mariana Islands. Correlation Tables 3 and 4 set out these correlations.
Selected species have been discussed or described and illustrated. The following species are new :
Textularia granulifera, Angulogerina capricornica, Operculina praevictoriensis, Parrellina heronica, Parrellina reticulata, Pulleniatina praeobliguiloculata.
Description: This item is only available electronically.Sat, 31 Dec 1960 14:30:00 GMThttp://hdl.handle.net/2440/932021960-12-31T14:30:00ZSpore trapping coupled with quantitative PCR : potential for application to biosecurity surveillance.http://hdl.handle.net/2440/93151
Title: Spore trapping coupled with quantitative PCR : potential for application to biosecurity surveillance.
Author: Vogelzang, Bernadette
Abstract: Plant disease surveillance is used in biosecurity to enable early detection of incursions of new pathogens, to monitor disease status during eradication programs, and to demonstrate that an area is free of a particular pathogen for trade purposes. Monitoring for plant pathogens currently relies on detection of symptoms by suitably skilled personnel, but the difficulties of distinguishing diseases based on symptoms, and of timing surveillance to coincide with symptom expression, can result in new pathogens not being detected until they are already widespread. The aims of this research were, firstly, to investigate the efficacy of spore trapping combined with quantitative PCR diagnostic assays for biosecurity surveillance and, secondly, to use the system to test predictions of spore release generated by epidemiological models. Methodology for detection and quantification of airborne spores using spore traps and quantitative PCR assays was optimised and tested on three model pathogens endemic on pulse and oilseed crops in South Australia:
1. Leptosphaeria maculans, cause of blackleg (phoma stem canker) of canola (oilseed rape, Brassica napus).
2. Didymella pinodes, which causes ascochyta blight (blackspot) of field pea (Pisum sativum), and
3. Ascochyta rabiei, cause of ascochyta blight of chickpea (Cicer arietinum).
The PCR tests were shown to be both specific and sensitive when applied to spore trap samples, and results were borne out by close correlation with microscopic counts of ascospores on tapes of trapped spores. Poor reproducibility of results was largely addressed by replication of PCR assays and use of an exogenous control to allow variation to be taken into account. Implications of the imprecision remaining in the system are discussed in relation to epidemiological research leading to biosecurity surveillance. Storage of spore trap samples at -20°C was found to be a suitable system for ascospores of L. maculans, with no reduction in the yield of DNA after 6 months. The finding that DNA yield from conidia of L. maculans was reduced, however, indicated that further research may be needed before applying these findings to other species and/or types of spore. The potential for reduced yield of DNA from spore trap samples collected during periods of extremely hot weather, and the possibility that dust may affect yields, were identified as factors to be considered in assessing qPCR results. Nevertheless, the system proved to be generally robust in weather conditions prevailing in southern Australia. The data from 2 years of monitoring for model pathogens were used to calibrate epidemiological models to the field site and to refine the models, as required. The findings that ascospores of D. pinodes were released during rain events in the summer led to incorporation of an additional cycle of ascospore formation and release, commencing during the cropping season, into the G1 Blackspot Manager model (model pathogen 1). Furthermore, the detection of D. pinodes DNA in spore trap samples on rainless days led to the incorporation of a relative humidity factor into the model. A minor modification was made to the Blackleg Sporacle model to smooth the model prediction curve (model pathogen 2). These changes, and the calibration of the models to the field site, need to be validated in further seasons. The results of monitoring for D. rabiei indicated that few or no ascospores were released from chickpea stubble, suggesting that the second mating type required for sexual reproduction, Mat 1-1, either does not occur in South Australia or is present as only a very small proportion of the population (model pathogen 3). In investigating questions arising from the above experiments, it was found that 7-month-old canola stubble exposed to prolonged dry conditions continued to release
ascospores immediately upon wetting, for up to 5 months (i.e. up until early summer, 12 months after harvest), but did not continue beyond the (Australian) early summer into the mid- and late-summer and autumn of the following year. This suggested that infested canola stubble from the season before the last is unlikely to be a significant source of infection for the current year’s canola crop emerging in autumn. DNA of D. pinodes was readily detected in dust generated at harvest but application of the dust to field pea seedlings failed to cause blackspot. The implications of these findings in relation to disease spread and biosecurity surveillance are discussed. The results obtained using the optimised methodology for spore trapping coupled with PCR diagnostics provided a good match with those obtained using trap plants, and with predictions of epidemiological models. Spore trapping coupled with qPCR proved to be a useful tool for epidemiological studies, which can be applied in biosecurity
surveillance.Sat, 31 Dec 2011 13:30:00 GMThttp://hdl.handle.net/2440/931512011-12-31T13:30:00ZStrangeness and charge symmetry violation in nucleon structurehttp://hdl.handle.net/2440/93138
Title: Strangeness and charge symmetry violation in nucleon structure
Author: Shanahan, Phiala Elisabeth
Abstract: The role of strange quarks in generating the structure of the nucleon provides a key testing-ground for our understanding of Quantum Chromodynamics (QCD). Because the nucleon has zero net strangeness, strange observables give tremendous insight into the nature of the vacuum; they can only arise through quantum fluctuations in which strange-antistrange quark pairs are generated. Strange observables are also relevant to searches for physics beyond the Standard Model; the role of the strange quark in generating the nucleon mass-encoded in the strange sigma term-is essential information for the interpretation of dark matter direct-detection experiments. For these reasons, strangeness in the nucleon is currently a particular focus of the nuclear physics community.
We use the numerical lattice gauge theory approach to QCD, and the chiral perturbation theory formalism, to build a clear picture of the role of strange quarks in various nucleon-structure observables. A detailed analysis of the octet baryon masses provides precise new values of the nucleon sigma terms. By combining experimental and lattice input, we deduce the strange electromagnetic form factors of the nucleon over a far larger range of momentum-scales than is accessible experimentally. Our calculation of the strange magnetic moment is an order of magnitude more precise than the closest experimental result.
Until now, the dominant uncertainty in experimental determinations of the strange proton form factors has come from a lack of knowledge about the size of charge symmetry violation (CSV) in these quantities. CSV effects quantify the breaking of the approximate SU(2)-flavour symmetry of the up and down quarks.
As well as their relevance to experimental determinations of nucleon strangeness, the precise knowledge of CSV observables has, with increasing experimental precision, become essential to the interpretation of many searches for physics beyond the Standard Model. We develop a formalism for the calculation of CSV observables from isospin-averaged 2 + 1-flavour lattice QCD simulations.
Applying this formalism to a comprehensive lattice-based study of the electric and magnetic Sachs form factors of the baryon octet reveals that the CSV form factors are an order of magnitude smaller than suggested by previous work. This calculation opens the door for new, precise, experimental measurements of the strange nucleon form factors. We also investigate the proton-neutron mass difference and quantify the long-neglected CSV effects in the low Mellin moments of the spindependent and spin-independent parton distribution functions. This analysis improves the interpretation of neutrino-nucleus deep inelastic scattering experiments.Wed, 31 Dec 2014 13:30:00 GMThttp://hdl.handle.net/2440/931382014-12-31T13:30:00ZEvidence for magmatic hydrothermal mineralisation at Kanmantoo Copper deposit, South Australiahttp://hdl.handle.net/2440/92910
Title: Evidence for magmatic hydrothermal mineralisation at Kanmantoo Copper deposit, South Australia
Author: Lyons, N. L.
Abstract: The Kanmantoo Cu-Au deposit is located 55km east of Adelaide, on the eastern edge of the Mt Lofty Ranges, South Australia. It is of Delamerian age and is hosted in the Tapanappa series of the Kanmantoo Group, a pelitic turbidite sequence metamorphosed to amphibolites facies. Models for mineralisation vary from sedimentary exhalative system to epigenetic mineralisation. Despite recent work, the structural evolution of the deposit is largely unknown and this allows for the absence of a definitive model for mineralisation. Detailed face mapping of the 1190RL bench in conjunction with handheld X-Ray Fluorescence Niton gun was adopted to further investigate the relationship between key structural features and element distribution. Micro analysis by petrographic studies, Edax element maps and δ34S isotope analysis was completed to gain understanding into fluid-rock relationships and origin of mineralising fluids. The findings of this study strongly suggest timing of copper mineralisation was associated with the first phase of orogenic extension at 490 ± 3 Ma. The extensional reactivation of compressional D3 shear zones, along with the injection of partially oxidised igneous derived fluids interacting with Fe-rich sediments, allows for the formation of the Kanmantoo magmatic hydrothermal deposit. Sulphur isotope results, and the mapping of magnetite-pyrite-chalcopyrite bearing K-feldspar veins are a very strong evidence of an igneous influence. Cu precipitation is as a result of a cooling oxidised magmatic hydrothermal fluids reacting with Fe in metasediments, and partially interacting with a reducing environment, rather than being directly associated with Fe rich metasomatism. Broad unmineralised zones of chlorite alteration suggest circulation of magmatic hydrothermal fluid with copper mineralisation preferentially precipitating in veins within and adjacent to reactivated D3 shears and D3 antiformal zones.
Description: This item is only available electronically.Sat, 31 Dec 2011 13:30:00 GMThttp://hdl.handle.net/2440/929102011-12-31T13:30:00Z